@kr4dio it's commercial (https://www.moonraker.eu/scanking-hf-discone-0-05-to-2000-mhz-antenna?___store=english). It is about 6 feet tall. I suspect the top section conceals a coiled up long wire or something but didn't fancy dismantling it before first use to find out. I doubt it is as effective as the full size model but it lets me scan the full range of my Airspy+Spyverter without switching antennas so it's a decent solution.